To read a document with the devices currently available on the market, a blind user must first capture an image of the document by placing the document in a scanner connected to a computer, then convert the text contained in the image into text codes by using Optical Character Recognition software previously installed in the computer, then use additional software to convert the text codes into synthetic speech or to convert the text codes into Braille codes which can then be sent to a tactile display connected to the computer.
Such an outfit is expensive, heavy and very difficult to carry around. Moreover, a scanner is designed to read flat documents, not book pages, particularly not inside thick hard cover books.
A device allowing blind individuals to read by touch printed objects within their hand reach had been invented in the early seventies by Dr. John Linvill, Professor at Stanford University. This device, called “Optacon” (meaning optical to tactile converter) comprised:
a rudimentary monochrome camera, comprising an array of 144 photosensors arranged in 6 columns of 24 sensors each, outfitted with a small lens providing to the sensor a variable size image of the surface of an object placed against the camera, the object being illuminated by a tiny lamp located near the camera lens, connected by a multi-wire cable to a small easy to carry box containing on one hand, a tactile reading array comprising, as the camera, 144 tactile stimulators similarly arranged in 6 columns of 24 sensors each, with a vertical pitch of 1.25 mm and a horizontal pitch of 2.5 mm, and on the other hand the electronic circuits needed to amplify the signals provided by the camera sensors and to mechanically vibrate the tactile stimulators corresponding to an active photosensor, this meaning a photosensor looking at a part of the object with a luminosity below a chosen threshold for a black on white text, or above a chosen threshold for a white on black text.
This device generated a tactile vibrating image of the small area of an object against which its camera was placed and moved.
As its use required a long and difficult training, even for blind people very proficient in Braille reading, many special “Optacon” training schools were then created with the financial support of the United States Government.
A few years later, when this financial support was terminated, most of these schools were closed, slowing down considerably the diffusion of Optacons among new users.
The appearance of new technologies, as for example Braille tactile displays driven by electromagnetic or piezo-electric actuators, combined with the development of personal computers, later allowed blind individuals to gain access to a growing number of documents available in digital computer formats.
The appearance of personal scanners, then of optical character recognition software, later allowed blind individuals to gain access to printed documents and triggered the termination of new Optacon manufacturing.
Since the disappearance of the Optacon, twenty years after its invention, blind individuals are deprived of the services it alone could provide: direct reading of printed objects inaccessible with a scanner either because of their shape—for example food can labels—or because of their position—clothes labels for example—or simply because of the lack of portability of a scanner-computer ensemble.